1. Field of the Invention
This invention relates to a vehicle which is driven by both an internal combustion engine using fuel and/or by an electric motor driven by electric power from a battery.
2. Description of the Related Art
One important difference between an electric vehicle and a vehicle driven by an internal combustion engine (ICE) is that the ICE-powered vehicle can be driven several hundred Km without refueling. On the other hand, if provided with a battery that can be charged to an extent to allow driving for several hundred Km, the electric vehicle's weight becomes excessive and, if provided. with a lighter weight battery that cannot be charged with as much electric power, the electric vehicle has a shorter traveling range.
In order to address the aforementioned limitations of an electric vehicle, a hybrid vehicle has been developed which has an internal combustion engine as an auxiliary power source. In the early stages of development of hybrid vehicles the internal combustion engine was used only after the battery had no remaining charge. More recent hybrid vehicles combine output from the internal combustion engine and output from the motor, relying on the internal combustion engine when high torque is required, for example, in accelerating the vehicle, and utilizing the motor to generate a torque allowing the ICE to use fuel with greatest efficiency or to power the vehicle without output from the ICE.
In the electric vehicle and hybrid vehicle, ideally the capacity of the battery will last until the vehicle is recharged in order to achieve the objectives of low-pollution and energy savings. However, once the capacity of the battery is exhausted during a journey, if an electric vehicle it cannot be driven further, and if a hybrid vehicle it must then be driven using only the internal combustion engine, with diminished driving performance in terms of pollution, energy efficiency and output. Therefore, electric vehicles and hybrid vehicles should have sufficient battery capacity to complete a journey.